Any advice?

[engstudent363]

I want to calculate the factorial of a number and have the results printed on the screen. If the number is -1 the program will exit. If the number is less than -1 the program will give an error message and ask for a new number. I've gotten everything taken care of except the whole calculate the factorial and have that result printed? Any advice? Specifics would be appreciated, not generic solutions. Here's what I got so far:

#include <stdio.h>

	int main() {

	   int big, num;

	   num = 5;
	
	while (num >= 0) {

	printf("Enter the number.\n");
	scanf("%d", &big);

	   if (big == -1) {
	   return 0;
	   }

	   if (big < -1) {
	   printf("ERROR - You have just entered a negative number, please enter a non-negative                                    number.\n");
	   num = 5;
	   }

	
	}

	

	}

[matsp]

Isn't this a repeat of a different post?

How would you go about calculating factorial if you had to do it with pen and paper. Write down how you would do it, in a way that would explain it step by step, to someone who hasn't got a clue how to do it [but knows how to do the four basic math operations].

Edit: perhaps one of the moderators can merge this thread with
http://cboard.cprogramming.com/showthread.php?t=99057
As it's the same subject and just a bit further along the road - no point in having two threads, I would say.

--
Mats

[esbo]

Wasn't this done using a recursive function?
One way of doing it I guess is like this?
Basically it's one line!!

#include <stdio.h>
int result,number;

main(int  argc, char *argv){

	result=1; //needs to be one as 0 times anything is 0.
	number=8; //for example

	while(number>=1) result*=number--;// you just need a line like this in your program

	printf("\n%d",result);

}

[matsp]

Wasn't this done using a recursive function?
One way of doing it I guess is like this?
Basically it's one line!!

#include <stdio.h>
int result,number;

main(int  argc, char *argv){

	result=1; //needs to be one as 0 times anything is 0.
	number=8; //for example

	while(number>=1) result*=number--;// you just need a line like this in your program

	printf("\n%d",result);

}

You can certainly do this with recursion, but it doesn't have to be [unless the assignment says so].

And the general principle in this forum is to not give the answer to assignments.

--
Mats

[manav]

mats, seems like you are getting too many PMs for home work help
*lol*

[Elysia]

int main(int  argc, char *argv){

Main returns int.
But you don't seem to understand that.

[matsp]

mats, seems like you are getting too many PMs for home work help
*lol*

Yes, I think out of the 40 odd PM's I've received, about 80% are "Can you please help me via instant messenger" or "I have this problem, can you please help me". I usually politely point out that I'm not a help-service, and I'm not available all hours [even if it may seem so].

--
Mats

[robatino]

Main returns int.
But you don't seem to understand that.

Not to mention the fact that it should be **argv (or *argv[]). Although I would have just left out argc and argv since they're not used in this program.